1. Field of the Invention
The present invention relates to the sequentially progressive settings of lie angles and head configurations of the iron clubs in an iron club set.
2. Description of the Related Art
In an iron club set consisting of a plurality of golf clubs including long irons to wedge-shaped clubs, its design has been made such that the lie angle progressively increases in value in going from long irons to short irons. That is, as going to short irons, the lie angles become upright.
Since the club length becomes short as going to short irons, the lie angles are rendered upright, thereby allowing the golf player to easily swing the club and not in an unnatural posture.
Manipulation of the club generally increases in difficulty as going to long irons. In particular when a powerless golf player of ordinary skill swings the golf club, the club frequently lags in swing. As a result, the golf ball is hit in a state that the club face is turned rightward (in the case of the right-handed player) with respect to the target direction. Consequently, the ball as hit is frequently sliced (in the case of the right-handed player, the ball is curved rightward). Recently, to increase a flying distance of the ball, the golf club of the called strong loft type progressively increases its market share. This type of the club is designed such that the shaft length of the club is longer than that of the conventional one by 0.5 to 1.5 inches, and the loft angle of the club is smaller than that of the conventional one by 2 to 3 degrees. This ball-slicing problem still more attracts a marked attention.
Accordingly, an object of the present invention is to provide an iron club set which lessens the difficulty in manipulating the golf clubs, particularly a chance of giving rise to the ball-slicing, and makes it easy for the golfer to take a stance without any strain in addressing the ball.
To achieve the above object, a first invention provides an iron club set wherein when the club heads of those clubs being such that the soles of them are placed on a horizontal surface, the loft angles and the lie angles are the regular ones, and those club heads are put in a normal addressing posture, are viewed from the front of the club head, a lie angle as an angle developed between the ground line and the shaft axis is set at 61 degrees or larger, the lie angles of the iron clubs including short irons to long irons are set at a fixed value, and a ratio (L/H) of the minimum height (L) of the face at the heel to the maximum height (H) of the face of the club head increases in value in going from short irons to long irons.
Alternatively, in a second invention, the lie angles increase in value in going from short irons to long irons.
One of the major causes to give rise to the slicing of the ball hit by the long iron is that when the ball is hit with the golf club, the head face is not perpendicular to an intended ball flying direction (target direction), but is directed rightward (in the case of the right-handed golfer). In other words, the major cause is that when the head impacts on the ball, the direction perpendicular to the club head is not parallel to the target direction.
It is known that when the lie angle of the club head is increased, the face is directed leftward. Therefore, in the invention, a large lie angle (61 degrees or greater) of the short iron which is determined so as no impair the easy manipulation of the short iron is employed for all the iron clubs in the set. By so selected, the lie angles of the long irons are larger than that of the conventional ones. As a result, when the golf player of ordinary skill hits the ball, the head face is corrected to be directed perpendicular to the target direction, thereby eliminating the slicing of the ball. Further, in the short irons, their lie angles are left large in value. The easy-to-swing feature is sustained even though the club length is short.
Also, in the second invention, for the like reason, the lie angles increase in value in going from short irons to long irons.
In this case, any of the lie angles (61 to 64 degrees) which have empirically been selected so as not to impair the easy-to-swing of the iron club, is preferably used for the lie angle of the short iron.
In the invention, the lie angle is limited to a value of 61 degrees or greater. In selecting the lie angles of the iron clubs in the set, it is preferable that the lie angle of each of the long irons is within 65 degrees. The reason for this is that if the lie angle of the long iron exceeds 65 degrees, when the player addresses the ball, the toe end extremely rises, so that it is difficult to hit the ball at the center of the head face.
In the invention, the lie angles of the middle irons and long irons are selected to be larger than of the conventional ones. Therefore, when the club head is put for addressing, the toe side considerably rises, and the player will possibly have an unnatural feeling. To cope with this, in the invention, a ratio (L/H) of the minimum height (L) of the face at the heel to the maximum height (H) of the face of the club head increases in value in going from short irons to long irons.
Usually, the upper end (top line) of the club head is configured such that it monotonously inclines from the maximum height portion of the face toward the heel In connection with this, in the invention, the ratio (L/H) is defined as mentioned above. By so defined, in the long irons within the set, the top lines of them are gentle in slant and substantially flat. As a result, the unnatural feeling caused by the extreme rise of the toe end at the time of ball-addressing is successfully eliminated.
In the invention, long irons include Nos. 1 to 3, middle irons includes Nos. 4 to 6 irons, and short irons include Nos. 7 to 9 irons.